Journal of Hazardous Materials 244–245 (2013) 251–258 Contents lists available at SciVerse ScienceDirect Journal of Hazardous Materials jou rn al h om epage: www.elsevier.com/loc ate/jhazmat Computational fluid dynamics simulation of transport and retention of nanoparticle in saturated sand filters Ashraf Aly Hassan a , Zhen Li b , Endalkachew Sahle-Demessie a,∗ , George A. Sorial b a U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA b School of Energy, Environmental, Biological, and Medical Engineering, Environmental Engineering Program, University of Cincinnati, Cincinnati, OH, USA h i g h l i g h t s ◮ Breakthrough curves used to study fate of NPs in slow sand filters (SSF). ◮ CFD simulate transport, attachment/detachment of NPs in SSFs. ◮ CFD predicted spatial and temporal changes for transient concentrations of NPs. ◮ CFD predicts low concentrations and steady NP influx would not be retained by SSFs. ◮ Pulse input is retained with outlet concentration of 0.2% of the inlet. a r t i c l e i n f o Article history: Received 28 August 2012 Received in revised form 31 October 2012 Accepted 7 November 2012 Available online xxx Keywords: Computational fluid dynamics (CFD) Nanoparticles Flow through porous media Modeling transport and deposition a b s t r a c t Experimental and computational investigation of the transport parameters of nanoparticles (NPs) flow- ing through porous media has been made. This work intends to develop a simulation applicable to the transport and retention of NPs in saturated porous media for investigating the effect of process conditions and operating parameters such, as ion strength, and filtration efficiency. Experimental data obtained from tracer and nano-ceria, CeO 2 , breakthrough studies were used to characterize dispersion of nanoparticle with the flow and their interaction with sand packed columns with different heights. Nanoparticle trans- port and concentration dynamics were solved using the Eulerian computational fluid dynamics (CFD) solver ANSYS/FLUENT ® based on a scaled down flow model. A numerical study using the Navier–Stokes equation with second order interaction terms was used to simulate the process. Parameters were esti- mated by fitting tracer, experimental NP transport data, and interaction of NP with the sand media. The model considers different concentrations of steady state inflow of NPs and different amounts of spike concentrations. Results suggest that steady state flow of dispersant-coated NPs would not be retained by a sand filter, while spike concentrations could be dampened effectively. Unlike analytical solutions, the CFD allows estimating flow profiles for structures with complex irregular geometry and uneven packing. Published by Elsevier B.V. 1. Introduction Industrial and consumer market for engineered nanoparticles (NPs) have been growing over the past decade. The commercial production and utilization of the NPs is anticipated to dramati- cally increase in the next few decades [1]. Such wide use of nano enabled materials could lead to the release of NPs into the environ- ment during manufacturing, transport, application, and end-of-life. Commercial applications of NPs include sunscreens, paints, tires, lubricants, shampoos and drug delivery, medical use, and electronic ∗ Corresponding author. Tel.: +1 513 569 7739. E-mail address: sahle-demessie.endalkachew@epa.gov (E. Sahle-Demessie). devices. Technological development and application are out-pacing research in health and environmental risk. In the last decade the research efforts has focused on the toxicity and human health effects of NPs [2,3], as well as their mobility and transport [4,5]. Correct prediction of the transport and fate of colloidal parti- cles in saturated porous media is of practical interest for many environmental applications, including transport of colloids and colloid-associated pollutants in groundwater and natural filtration of microorganisms in a deep-bed filtration in water and wastewater treatment. Once released into the environment, NP could be transported to the ground water reserves. The mobility of NPs in groundwater aquifers and sand filters is a critical property affecting their fate and transport. The aggregation and mobility of NPs in porous 0304-3894/$ – see front matter. Published by Elsevier B.V. http://dx.doi.org/10.1016/j.jhazmat.2012.11.021